1. Field of the Invention
The present invention is directed to a stator of an electric machine, particularly for a hybrid vehicle or electric vehicle, with a substantially cylinder-jacket-shaped, axially extending stator carrier, which stator carrier carries a lamination stack with a plurality of stator teeth which are substantially annularly arranged and has a radially inwardly extending shoulder edge which serves as axial support for the lamination stack.
2. Related Art
As is known from the art, a stator of the type mentioned above is used particularly for electric machines, for example, electric motors or generators. Electric motors or generators of this type have a stationary component part (stator) and a component part (rotor) that rotates relative to the stator. The stator is generally fixedly arranged at a housing. Electric machines of this type are used particularly in electric vehicles or hybrid vehicles, which have an advantage over conventional vehicles with regard to energy consumption. However, the electric motors or generators used in electric vehicles or hybrid vehicles of this type must deliver high outputs and torques, which entails high waste heat through resistive losses in the stators. To prevent any damage resulting from this waste heat, it is customary to arrange at least one cooling system at the stator so that the waste heat can be dissipated. In this respect, a distinction is usually made between active cooling, in which a coolant is actively guided, via additional elements, to the stator, and passive cooling systems in which, for example, a coolant that is already being used for the clutch is guided outward to the stator via centrifugal forces.
DE 10 2008 001 622, for example, discloses an active cooling system in which coolant is sprayed directly on the stator or stator coil windings via coolant nozzles. It is also known to guide coolant through coolant channels additionally formed at the stator so as to dissipate waste heat as is disclosed, for example, in DE 10 2011 103 336. In passive cooling systems, as mentioned above, coolant that is used, for example, to cool an internal clutch or a rotor, and is carried outward by centrifugal forces, is also used to cool the stator.
In both systems, the coolant, after passing the stator, usually impinges on the housing wall and runs down it to a coolant trough. Further, by impinging against the walls of the housing, the coolant is defoamed so that the coolant can easily drain into the coolant trough.
However, a disadvantage in all of the coolant systems known from the prior art consists in that, particularly in the region of the coolant trough, coolant removal is often insufficient because more coolant enters the coolant trough than is drained off. Although an overflow opening that can remove excess coolant is known from the prior art, it is not designed to provide continuous removal of coolant. Further, an overall increase in the coolant throughput in the entire system, for example, to compensate load maxima, is impossible.